Decorated transparent article



Nov. 4, 194-1.

c. A. BAUER DECORATED TRANSPARENT ARTICLE Filed June 10, 1940 1 NV EN TOR. awn? 5 s A? 5/7052,

Patented Nov..4, 1941 DECORATED TRANSPARENT ARTICLE Charles A. Bauer, Newburg, Ind., assigncr to The Cardinal Corporation, Evansvilie, Ind., a corporation of Indiana Application June 10, 1940, Serial Ne. 339,729

6 Claims. (Cl. 41 22) This invention relates to transparent articles of the type in which the rear face is recessed to form a design, the walls of the design-forming recesses (and usually the unrecessed portions of the rear face of the article also) being provided with an opaque coating of paint or similar material. In such articles, the design possesses an actual three-dimensional character which tends to make it stand out, in appearance, from its background. However, since the design is 11- luminated only by light which passes through the transparent body of the article, and since such light is refracted toward the normal as it enters such transparent body, the illumination of the design is necessarily relatively flat and not such as will produce more or less pronounced shadows tending to make the design stand out in its threedimensional character. In many instances, especially when the coating on the recess walls is of a dark color, it is deemed necessary to coat the unrecessed portions of the rear face of the article with a coating of a contrasting color in order to make the design sufiiciently distinguishable from its background; but even then, the actual threedimensional character of the design may not be clearly apparent. Moreover, the application of paints of contrasting colors to the recess walls and background requires two operations, one of which involves the step of removing paint from certain surfaces or preventing it from reaching those surfaces; and, as a result, the finishing of the articles with paints of contrasting colors is a rather troublesome and expensive process.

It is the broad object of my invention to enhance the appearance of designs formed in plastic articles as above described, to make the threedimensional character of the design more readily apparent, and to render the details of the design more readily distinguishable. In the particular form illustrated and described herein, a more specific object of my invention is to produce a readily distinguishable design which will stand out from its background, and to do so with a coating of a single color, which may even be a dark color, applied to both the rear face of the surface portions'which'lie approximately parallel to usual lines of vision. I then apply to the recess walls a coating of a character distinguished from the coating produced by ordinary pigment paints in that the degree to which it disperses light incident upon it is relatively small. Since the design will necessarily be illuminated by light passing through the transparent body of the article, those surfaces of the design which are disground, even when that background is formed by a coating of the same color asthat applied to the walls, of the design-forming recesses. I

The accompanying drawing illustrates my invention: Fig.1 is an isometric view of a section of a transparent article in which the design consists of the numeral I, and Fig. 2 is a fragmental transverse section through the article illustrated in Fig. 1.

Although not limited thereto, my invention is especially useful and valuable in connection with designs consisting of or comprising letters, numerals, graduations, or other indicia on instrument-dials, escutcheon plates, name plates, etc. for the application of the invention makes the designreadily distinguishable without the necessity of employing two colors to obtain contrast. The possibility of eliminating two-color coatings is obviously of particular advantage when the rewhen consisting of letters, figures, or graduations.

article and to the walls of the design-forming spective angles to any customary line of vision will differ widely; and, most desirably, so that the recess walls will present some surfaces or surface portions which lie approximately perpendicularv to usual lines of vision and other surfaces or perpendicular to any normal line of vision.

The article illustrated in the drawing consists of a portion of a sheet ll) of transparent material, conveniently of molded plastic material such, for example, as cellulose acetate. The design, here illustrated by way of example as consisting of the numeral l, is formed by recessing the rear face of the article in the desired pattern. As previously indicated, I prefer to form the recess with walls or wall-portions whose respective angles to any normal line of vision will difier widely. Thus, in the particular article illustrated, the side walls ll of the recess will be approximately parallel and the bottom wall I2 approximately As shown in Fig. 2, both side walls II and the bottom wall I2 are approximately plane and meet each other at a relatively well defined edge; but

is not essential. For example, the recessthe curved portions merging smoothly into each other, or the recess-walls might consist of a single smoothly curved surface. However, in securing the most pronounced beneficial results in the practice of my invention'it is advisable that the wall or walls of the recess include portions which, in cross-section, are at markedly different angles to any usual line of vision.

With the recess desirably formed as just set forth, the walls thereof are coated with a coating l3 of opaque material which may, as illustrated in Fig. 2, extend over the unrecessed portions of the rear face of the article I. As previously indicated, this coating is of a character such that the interface between it andthe recess-wall will possess materially less light-dispersing power than does ordinary ground-pigment paint. I have obtained the most satisfactory results with coating material comprising a metallic pigment suspended in a volatile vehicle which includesa dye of the desired color, and which also includes or consists of a volatile solvent for the material of which the article I is formed, as set forth in my co-pending application Serial No. 265,746, filed April 3, 1939. The metallic pigment which I prefer to employ is formed by the disintegration of metal foil, with the result that the individual pigment-particles are in the form of relatively flat flakes, in contradistinction to the gen-' erally spheroidal form which characterizes conventional ground pigments such, for example, as white lead. I have found that a coating material of the preferred form can be applied in such a manner that, when it dries, the flakes of metallic pigment adjacent the interface will be more or less oriented in positions generally parallel to that interface; and, as a result, light reflected from the interface is dispersed to an extent materially less than it would be if the coating comprised a ground pigment or unoriented plane particles.

Since light illuminating the coating I3 must pass through the transparent material constituting the article ID, wall surfaces, such as the wall [2, which are generally perpendicular to any usual line of vision will tend to reflect toward the front face of the article light which is incident upon them; while surfaces, such as the side walls H, which form the edge portions of the design and which are generally parallel to the line of vision will tend to reflect light incident upon them toward the rear face of the article. As a result, to an observer located at the point A, for example, the former wall surfaces will appear materially brighter and lighter than the latter. Because of the contrast in shade between surfaces or surface portions disposed at materially different angles to the line of vision, the design formed by the coated recess walls stands out very effectively in its three-dimensional character and is clearly distinguishable even from a background of the same color. curved in cross-section are very effectively high lighted.

In situations where the outer or free surface of a metallic-pigment coating is to be viewed, it is recognized that the vehicle in which the metallic pigment is suspended should desirably be of a character promoting uniform dispersion of the pigment particles; for, if the vehicle contains any ingredient or possesses a pH value which tends to cause ag regation of the pigment par- Recess surfaces which are ticles, the resultant surface possesses relatively walls might appear curved in cross-section with in the practice of my invention where it is the inner or bond surface of the coating which is visible. When, as is preferable, the coating material employs a vehicle containing or consisting of a-volatile solvent for the material-of which the article is formed, I find it desirable to apply the coating in as dry a form as possible. In spraying, which is usually the most satisfactory method of applying the coating, I therefore prefer to hold the spray nozzle at a distance from the work light-dispersing qualities of the interface.

I claim as my invention:

1. A transparent article having substantially plane parallel front and rear faces, said article being provided in its rear face with a recess forming a design, the recess walls having portions near the edges of the design which are approximately perpendicular to the front and rear faces of the article and intermediate portions which are approximately parallel to such front and rear faces, the walls of the design-forming recess being provided with an opaque coating which is visible through the article and which comprises flakes of metallic pigment oriented generally parallel to the adjacent portion of the recess-wall.

2. A transparent article having substantially plane parallel front and rear faces, said article being provided in its rear face with a recess forming a design, the recess walls having portions near the edges of the design which are approximately perpendicular to the front and rear faces of the article and intermediate portions which are approximately parallel to such front and rear faces, the walls of the design-forming recess being provided with an opaque coating which is visible through the article, and the-front face of which possesses light-dispersing properties of the order of those possessed by a coating comprising flakes of metallic pigment oriented in generally parallel relationship.

3. A transparent article having front and rear faces and provided in its rear face witha recess forming a design, the recess walls having portions near the edges of the design which are approximately parallel to a normal to the front face of the article and intermediate portions approximately perpendicular to such normal, the walls of the design-forming recess being provided with an opaque coating which is visible through the article and which comprises flakes of metallic pigment oriented generally parallel to the adjacent portion of the recess-wall.

4. A transparent article having front and rear facesand provided in its rear face with a recess forming a design, the recess walls having portions near the edges of the design which are approximately parallel to a normal to the front face of the article and intermediate portions approximately perpendicular to such normal, the walls of the design-forming recess being provided with an opaque coating which is visible through the article and the front face of which possesses light-dispersing properties of the order of those possessed by a coating comprising flakes of metallic pigment oriented in generally parallel relationship. I

5. A'transparent article having front and rear forming a design, the recess walls having portions making materially diiferent angles with a normal to the-front face of the article, the walls of the design-forming recess being provided with an opaque coating which is visible through the article and the front face of which possesses light-dispersing properties of the order of those possessed by a coating comprising flakes of metallic pigment oriented in generally parallel re- 10 lationship.

CHARLES A. BAUER 

